Move uplink file information to build.info files

Move uplink file information to build.info files

This file information was hidden in config target files, when they
should really be part of build.info like any other file we build
from.  With build.info variables, the task became much easier.

We take the opportunity to move apps_init_src and apps_aux_src to
apps/build.info as well, and to clean up apps/build.info.

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9166)